A radio communication receiver has importance of standby power reduction during reception standby. Particularly, a PLL circuit used for a local oscillator considerably contributes to power consumption of the entire receiver. Conventionally, the following technique has been proposed for a measure for standby power reduction in the PLL circuit. A switch is interposed between a charge pump and a low pass filter in the PLL circuit, and electric charges are charged in the low pass filter while the switch is on. When the switch is turned off after that, supply of power to the charge pump is suspended and additionally the electric charges charged in the low pass filter are used so that an oscillation frequency of a power controlled oscillator remains constant.
However, the electric charges charged in the low pass filter discharge as time passes so that a frequency and a phase of an oscillation signal of the voltage controlled oscillator gradually shift. The oscillation frequency is not locked to a desired frequency so that the frequency and the phase of the oscillation signal may shift further due to phase noise of the oscillator itself. After that, when the switch is on and then PLL control resumes, a large phase error is detected immediately after the resumption. Even when no shift provisionally occurs in the oscillation frequency, the oscillation frequency temporarily considerably varies. Accordingly, the conventional measure for the standby power reduction cannot suspend the PLL control over a much long period so that there is a problem that the power consumption cannot be much reduced. The above effect due to phase noise of the oscillator itself cannot be solved even when a measure is performed against the discharge of the electric charges in the low pass filter.